From 7d431f1c8f66810cc7428705df695739346837d2 Mon Sep 17 00:00:00 2001
From: Mohammed Sohail <sohailsameja@gmail.com>
Date: Sat, 14 May 2022 11:15:45 +0300
Subject: [PATCH] add: (wip) balances query API

---
 cmd/init.go                 |  7 +++++++
 cmd/server.go               |  2 ++
 config.toml                 |  1 +
 internal/public/api.go      | 28 ++++++++++++++++++++++++++++
 internal/public/balances.go | 31 +++++++++++++++++++++++++++++++
 queries/public.sql          |  6 ++++++
 6 files changed, 75 insertions(+)
 create mode 100644 internal/public/api.go
 create mode 100644 internal/public/balances.go
 create mode 100644 queries/public.sql

diff --git a/cmd/init.go b/cmd/init.go
index 00a76d5..a95efad 100644
--- a/cmd/init.go
+++ b/cmd/init.go
@@ -34,6 +34,7 @@ type config struct {
 type queries struct {
 	core      goyesql.Queries
 	dashboard goyesql.Queries
+	public    goyesql.Queries
 }
 
 func loadConfig(configFilePath string, k *koanf.Koanf) error {
@@ -97,9 +98,15 @@ func loadQueries(sqlFilesPath string) error {
 		return err
 	}
 
+	publicQueries, err := goyesql.ParseFile(fmt.Sprintf("%s/public.sql", sqlFilesPath))
+	if err != nil {
+		return err
+	}
+
 	preparedQueries = &queries{
 		core:      coreQueries,
 		dashboard: dashboardQueries,
+		public:    publicQueries,
 	}
 
 	return nil
diff --git a/cmd/server.go b/cmd/server.go
index 5f38e19..f56f2e2 100644
--- a/cmd/server.go
+++ b/cmd/server.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"cic-dw/internal/dashboard"
+	"cic-dw/internal/public"
 	"github.com/labstack/echo/v4"
 	"github.com/labstack/echo/v4/middleware"
 )
@@ -18,6 +19,7 @@ func initHTTPServer() *echo.Echo {
 	}))
 
 	dashboard.InitDashboardApi(server, db, preparedQueries.dashboard)
+	public.InitPublicApi(server, db, preparedQueries.public)
 
 	return server
 }
diff --git a/config.toml b/config.toml
index d4b546e..de6f4d8 100644
--- a/config.toml
+++ b/config.toml
@@ -13,6 +13,7 @@ cors = [
 
 [chain]
 index = "0x5A1EB529438D8b3cA943A45a48744f4c73d1f098"
+balances_resolver = "0x9C48FF0888A747Ba0108E7205Cae2EeB0C76c948"
 rpc   = "http://127.0.0.1:8545"
 
 [syncers]
diff --git a/internal/public/api.go b/internal/public/api.go
new file mode 100644
index 0000000..cc72757
--- /dev/null
+++ b/internal/public/api.go
@@ -0,0 +1,28 @@
+package public
+
+import (
+	"github.com/jackc/pgx/v4/pgxpool"
+	"github.com/labstack/echo/v4"
+	"github.com/nleof/goyesql"
+)
+
+type api struct {
+	db *pgxpool.Pool
+	q  goyesql.Queries
+}
+
+func InitPublicApi(e *echo.Echo, db *pgxpool.Pool, queries goyesql.Queries) {
+	g := e.Group("/public")
+
+	g.Use(func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			c.Set("api", &api{
+				db: db,
+				q:  queries,
+			})
+			return next(c)
+		}
+	})
+
+	g.GET("/balances/:address", handleBalancesQuery)
+}
diff --git a/internal/public/balances.go b/internal/public/balances.go
new file mode 100644
index 0000000..739776d
--- /dev/null
+++ b/internal/public/balances.go
@@ -0,0 +1,31 @@
+package public
+
+import (
+	"context"
+	"github.com/georgysavva/scany/pgxscan"
+	"github.com/labstack/echo/v4"
+	"net/http"
+)
+
+type dbRes struct {
+	TokenSymbol  string `db:"token_symbol"`
+	TokenAddress string `db:"token_address"`
+}
+
+func handleBalancesQuery(c echo.Context) error {
+	var (
+		api  = c.Get("api").(*api)
+		data []dbRes
+	)
+
+	rows, err := api.db.Query(context.Background(), api.q["all-known-tokens"], c.Param("address"))
+	if err != nil {
+		return err
+	}
+
+	if err := pgxscan.ScanAll(&data, rows); err != nil {
+		return err
+	}
+
+	return c.JSON(http.StatusOK, data)
+}
diff --git a/queries/public.sql b/queries/public.sql
new file mode 100644
index 0000000..7946e98
--- /dev/null
+++ b/queries/public.sql
@@ -0,0 +1,6 @@
+-- name: all-known-tokens
+-- Looks up all known tokens from the transactions records
+SELECT DISTINCT tokens.token_symbol, tokens.token_address FROM transactions
+INNER JOIN tokens on transactions.token_address = tokens.token_address
+WHERE transactions.sender_address = $1
+OR transactions.recipient_address = $1;